said researchers reporting a review of more than 1,000 young women with breast cancer, mostly in Europe but also Israel and North and South America.
It’s been known that pregnancy after breast cancer treatment, even for hormone receptor–positive disease, is safe overall, the team commented. However, there have been concerns about women who have BRCA mutations because of a lack of data.
The new findings “provide reassurance to patients with BRCA-mutated breast cancer interested in future fertility” and are of “paramount importance for health care providers involved in counseling young patients,” said the researchers, led by Matteo Lambertini, MD, PhD, a medical oncologist at the University of Genoa, Italy.
The review was published in September in the Journal of Clinical Oncology.
The team reviewed reproductive outcomes among 1,252 women who were no older than 40 years when diagnosed with stage I-III BRCA-mutated invasive breast cancer between January 2000 and December 2012.
More than half (65%; n = 811) had BRCA1 mutations, 430 women (34%) had BRCA2 mutations, and 11 women had both.
Overall, 195 women became pregnant, at a median of 4.5 years after the breast cancer diagnosis and at a median age of 36 years.
The miscarriage rate was 10.3%, lower than expected in the general population.
Among the 150 patients who gave birth to 170 infants, delivery complications occurred in 13 of the 112 pregnancies with available data (11.6%), and congenital anomalies were seen in just 2 pregnancies (1.8%). This is a lower rate of anomalies than expected in the general population, the team noted. The rate of preterm delivery was 9.2%, similar to the general population.
There was no difference between the women who became pregnant and those who did not in either disease-free survival (adjusted hazard ratio, 0.87; P = .41) or overall survival (aHR, 0.88; P = .66), over a median follow-up of 8.3 years from diagnosis. In addition to BRCA mutations, the analysis adjusted for age at diagnosis, tumor size, nodal status, hormone receptor status, type of endocrine therapy, and breast surgery.
Over 80% of the subjects had ductal carcinoma, and over 90% of women were HER2-negative. More women in the pregnancy cohort had tumor diameters of 2 cm or less (47.2% vs. 40.9%) and a higher percentage had breast conserving surgery (59% vs. 45.9%).
Chemotherapy was administered to 95.3% of the subjects, most commonly anthracycline and taxane based, and more than 90% received endocrine therapy, most often tamoxifen alone among women who did not become pregnant and tamoxifen plus a luteinizing hormone-releasing hormone agonist among those who did. Endocrine therapy was shorter among women who became pregnant (median, 50 vs. 60 months; P < .001).
The findings held when 176 pregnant cases were matched to 528 nonpregnant controls for year of diagnosis, nodal status, hormone receptor status, and type of BRCA mutation. However, disease-free survival was improved among pregnant women (HR, 0.71; P = .045) who were younger at diagnosis, with median ages of 31 years vs. 36 years (P < .001).
The study was funded by the Italian Association for Cancer Research, among others. Dr. Lambertini reports acting as a consultant for Roche and Novartis and as a speaker for Theramex, Takeda, Roche, Eli Lilly, Novartis. Several coauthors also report relationships with pharmaceutical companies, as detailed in the original article.
A version of this article originally appeared on Medscape.com.